Growing up, I thought my city, Madras (that is also Chennai) was just unfortunate to be permanently water-starved. We were dependent on the monsoons to fill up the city’s reservoirs and recharge groundwater. The weather and whether the monsoons would be good this year were favourite subjects of discussion among its denizens.

Then I happened to see an exhibition of old maps, carefully hand-drawn and prettily-coloured, from the 1600s when the ‘city’ was ‘established’ by the British. The maps, dated down to the late 1960s, were a revelation; the city had had many eris, ponds, tanks, and so on which were clearly documented. Further reading and peregrinations in the city, led to the realisation that there are still street (Tank Bund Road in Nungambakkam, Lake View road in Kottur) and locality names (Velachery, Retteri for example) that reflect this rich ecological history that as a city we have systematically buried.

So to read that, 2.5 years after the 2015 floods, the powers that be in The Ripon Building (the seat of the Corporation) have woken up to the importance of these waterbodies and called for their restoration is heartening.

Adopt a Waterbody

According to media reports, the Greater Chennai Corporation (GCC) has called on corporates, non-profits, and anyone with the wherewithal and interest to step forward to ‘restore’ the city’s waterbodies. Some 200 odd waterbodies are up for ‘adoption’. From talking to the GCC we understand that they want interested groups to choose a waterbody, develop a plan for it with a cost estimate. Once this is approved by the GCC, the organisation must, within 3 months, finish the work and hand over the waterbody back to the GCC. What does the organisation stand to benefit? They may, with approval, set up a board near the waterbody noting their contribution to its restoration and this of course serves to fulfil their CSR requirements.

On asking if the GCC has some long-term plan to maintain these waterbodies once they are ‘restored’, I was informed that they had no plan and that hurdle would be dealt with when it came.

On visiting the GCC, we found that it is, through the Tamil Nadu Urban Infrastructure Financial Services Ltd (TNUIFSL), getting feasibility reports and cost estimates done for restoration of a number of the waterbodies. We perused a few and found the focus is on desilting, dredging, deepening, and creating bunds to allow for greater water collection during the monsoons.

While it is great to see the Corporation take up this serious problem of water security in the city, the scheme also throws up some important questions that need to be addressed if Chennai wants to be truly water sufficient and resilient.

The restoration bogey

Restoration always conjures up the image of returning something to a utopian, pristine idyll harking back to the past. This assumes that that something from the past is actually the perfection that we need to aim for. But is it?

When it comes to the eris of Chennai, these are not actually natural waterbodies. The eris are more a series of tanks or ponds constructed years ago by our prescient ancestors to collect and manage water for their needs. One might argue that though humans in the past have modified the environment to create these waterbodies, these are now the natural state of things. (This reminds me of an argument that a senior forest department official made to me that Prosopis – that much hated invasive plant – has become a native now because it was introduced years ago!)

I think it’s not about ‘going back to the original or natural’ as this is a slippery slope depending on how far you turn the clock back and what level of human interference is considered acceptable. Rather, instead of talking of ‘restoration’, one should talk about ‘rehabilitation’ because that is truly what most restoration projects are about. They are about improving the condition of the waterbody. Usually this rehab takes a strongly ecological perspective while keeping in mind social uses and needs.

In India though, restoration (aka rehabilitation) is only focused on increasing water retention capacity by dredging and a ‘beautification’ of the waterbody edge. The beautification is usually all about having walkways for joggers and creating other such recreational spaces with grassy areas, etc.  What this approach ignores is that not all waterbodies are alike. In fact, what we happily club as lakes are not all lakes and are quite varied ecologically. In addition, the ecology of any given ‘lake’ varies depending on a number of factors.

Diverse in every which way

Ponds, lakes, and marshes are typically depressions of varying size that hold fresh or brackish water, are surrounded by land though they may have a connection to the ocean or to other lakes, ponds. Just this rather simple definition throws up a whole lot of variables. These waterbodies vary in size which means they vary in the amount of water they hold and therefore the species of plants and animals they can support. Many of them also vary in size from season to season.

Then they vary in depth and it is not necessary that the deepest part of the waterbody is at the centre! So the amount of light and heat reaching the bottom varies. In many lakes, there is a temperature gradient i.e the water on the surface is warmer than the water at the bottom. This temperature gradient varies with time of day (diurnal variation) and season. Depending on the amount of sunlight, different plants thrive in different parts of the lake and this influences the animal life and all of this affects the chemical parameters of the water (dissolved oxygen, TDS, turbidity, etc).

Then there is the edge of the waterbody which hosts a different set of species as it is sometimes submerged (to varying degrees) and sometimes exposed. Rain and other runoff bring not just water to the lake but also silt and nutrients (including through sewage). All of this causes the chemical, physical and biological parameters of the lake to shift.

Thus, what to our untrained human eye, looks a quiet, pretty expanse of water is, in reality, a complex ecosystem that is constantly in flux. And we haven’t even touched upon the geology of the area which also has a part to play.

One size does not fit all

You may think, okay I get it; lakes are complex. The point, though, is that our rehabilitation methods are, therefore, not suited to these complex ecosystems. Most rehabilitation exercises dredge and de-silt the waterbody, scooping out the lake bed in a U shape with no thought to how that changes the ecology of the lake. Such plans also tend to prohibit certain users such as livestock herders (from bathing their livestock), washermen, fishers, etc, for aesthetic reasons.

While there are inherently classist problems with such exclusion, there is also an ecological component as these users of the waterbody modify the nutrient inflow into the system and therefore excluding them could have untoward impacts.

Rehabilitation of waterbody then is no small undertaking. A good understanding of the chemico-physico-biological complex is essential. Excavating some metres of soil, planting some trees and waiting for the monsoon to fill up the cavity, does not rehabilitation make.

That would be creating a completely new waterbody.